It's waaay overkill for this type of use, but I'd happily grab my FAL on my way out the door. The carbine version is of reasonable length, but the weight is a bit more than I'd want to carry for long distances (especially with other equipment and ammo). But despite these things, it has seen service all over the world in all types of climates. They tend to be extremely reliable, and can eat just about anything you feed them, thanks to the adjustable gas system. Spare parts used to be plentiful, but you'd have to check on this these days. DS Arms makes some excellent FALs. (In fact there are some currently in service in the Middle East with some of our SF guys.)

Besides, there is an online forum that is almost as fun as this one called the FALfiles. The folks there have tons of experience with these, and could help you more than I.